chore(deps): Update dependencies

[reneleonhardt]

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• You have read the contribution guidelines.
• You have created a feature request first to discuss your contribution intent. Please reference the feature request ticket number in the pull request.
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⬆️ 💡 Updates

• Update dependencies and plugins (except Mockito which switched to Java 11)
• Update Maven and Maven Wrapper
• Update GitHub Actions
• Let Dependabot update Maven and GitHub Actions

🐛 💚 Fixes

• Some compiler warnings (newer compiler plugin is stricter), the ConnectionPool constructor should be refactored (please analyze with javac and SonarLint)
• Some shell warnings
• Use Maven Wrapper in ci.yml (for windows)

🧑‍💻 Improvements

• Make POM more manageable (i.e. to use mvn versions:update-properties)

🎨 Recommendations

• Manage all dependency and plugin versions to improve build and client stability